Transformer with relatively movable core parts



March 30, 1965 J. sssss Rl 3,176,252

ATIVELY MO L ART March 30, 1965 J. sPlTr-:Rl 3,176,252

TRANSFORMER WITH RELATIVELY MOVABLE CORE PARTS Filed May 31, 1962 2 Sheets-Sheet 2 INVENTOR. Jasspn S rvrs/ United States ,Patent O 3,176,252 TRANSFORMER WITH RELATIVELY MOVABLE CORE PARTS Joseph Spiteri, 142W. 26th St., Erie, Pa. Filed May 31, 1962, Ser. No. 198,924 2 Claims. (Cl. 336-118) This invention relates to transformers and, more particularly, to variable voltage transformers.

Previously, reactor type electrical components have been provided utilizing a coil wound on an iron core. When the coil is connected in an electrical circuit, the impedance of the coil present in the circuit can be changed by varying the amount of iron in the core of the coil.

The present invention provides an improved transformer which makes it possible to actually elongate the iron path through which the flux lines generated by the primary coil must pass -in inducing an output voltage in the secondary coil. Thus, the secondary voltages can be varied by moving the fixed and movable coils With a segment of the core toward and away from the primary coil, thereby actually elongating the iron path.

It is, accordingly, |an object of the present invention to provide an improved transformer.

Another object of the invention is to provide a transformer which is simple in construction, economical to manufacture, and simple and efiicient to use.

A further object of the invention is to provide a transformer wherein the voltage of the -secondary winding is variable in precise small increments.

With the above and other objects in view, the present invention consists of the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawings and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions, and minor details of construction without departing from the spirit or sacrificing any of the advantages yof the invention.

In the drawings:

FIG. 1 is .an isometric view of a variable transformer according to the invention;

FIG. 2 is aside view partly in cross section of another embodiment of the invention;

FIG. 3 is an isometric view of still another embodiment of the invention;

FIG. 4 is an end View partly broken -away :showing the parts of the transformer; and

FIG. 5 is a view of one of the coils of the transformer.

Now with more particular reference to the drawing, FIG. 1 shows a transformer 10 having a xed core 11 and a movable core 12. These cores will be made of laminated iron in a conventional manner. Guide core members 15 and 16 are fixed .to the fixed core 11. These guide core members will preferably be laminated also to prevent eddy currents from being generated therein. The guide core members 15 and 16 will extend through openings 17 and 18 in the movable core 12; that is, the movable core 12 will be slidably received on the cylindrical guide core members 15 and 16. The fixed core 11 is U-shaped and has legs 19 yand 20 connected together by .an intermediate part and extending toward the movable core 12.

A suitable adjusting arrangement can be provided to move the movable core 12 relative to the xed core 11. This movable mechanism is indicated at 22 and it may be, for example, a screw land nut arrangement with a crank thereon which is of a type familiar to those skilled in the art. Therefore, the movable core can be moved in very small accurate increments relative to the fixed core.

A primary coil 13 is disposed `around the U-shaped fixed core 11 and a secondary coil 14 is disposed around the U-shaped movable core 12. These coils can be inter- 3,176,252 Patented Mar. 30, 1965 changed so that the primary coil would be the coil 14 and the second-ary coil would be coil 13. Also, only one coil could be used as a choke coil to lform an inductive irnpedance. The other coil could be left open or it could be short circuited to 4further modify the inductive reactance of the circuit.

In the embodiment of the invention shown in FIG. 2, the transformer is supported on ya mounting bracket and it has a core 111 fixed to the mounting bracket and a core 112 rotatably supported thereon with respect thereto. The cores 111 and 112 may be made of punched laminations or the like and they have windings 113 and 114, respectively, thereon.

The fixed core 111 is fixed to the mounting bracket 110 by means of bolts which are supported thereon by means of nuts 126. The two cores are xed to non-metallic members and 131. These non-metallic members are p-ivotally held together by means of a bolt 132 which extends therethrough and allows them to rotate relative to cach other.

A non-magnetic bracket member 133 is fixed to pole pieces 134 and 135 of the movable core 112 and a handle 136 is fixed to the bracket member 133. Likewise, a handle 137 i-s fixed to the end of the bracket member 133.

The pole pieces 134 and 135 have brush members 138 and 139 fixed thereto which are tapered similar to those shown in FIG. 4 so that when the handle 136 is rotated, the flux path from one core to the other is increased in length and, thereby, the reluctance of the transformer is changed and, also, the output voltage thereof.

In the embodiment of the invention shown in FIG. 3, a base 210 has a bracket 210 supported thereon. The U-shaped bracket 210' is made of non-magnetic material and supports a fixed core 211 thereon. A movable core 212 is rotatably supported by means of a handle 236 which is rotatably supported in a bracket 241. A nonmagnetic disk 233 is fixed to the movable core 212 by means of non-magnetic screws 247.

A coil 213 is wrapped around the core 211 and a mov able coil 214 is wrapped around the movable core 212. The movable core has pole pieces 234 and 235 fixed thereto and to the ends of these pole pieces are attached magnetic brushes 243 'and 244. Pole pieces 238 and 239 have brushes 246 attached thereto. The brushes 243 and 246 rub against each other so that .as the handle 236 is rotated, the effective length of the flux pat-h through the two cores is increased and this causes a decrease in the voltage between primary wires 221 and secondary wires 223.

'I'he foregoing specification sets forth the invention in its preferred practical forms but the structure shown is capable of modification within a range of equivalents without departing from the invention which is to be understood is broadly novel as is commensurate with the appended claims.

'Ihe embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A transformer comprising la U-shaped fixed core having legs and an intermediate part connecting said legs together and a movable core disposed with the legs of said U-shaped lcore facing toward said movable core, a iii-st coil on said fixed core and a second coil on said movable core, cylindrical guide core members fixed at one end to the legs of said U-shaped fixed core and extending there from `generally parallel thereto, said guide members on said iixed core extending through the legs of said movable core Iand slidably receiving said movable core, and means to adjust the position of said movable core on said guide core members whereby the length of magnetic circuit through said cores is increased.

2. A variable output transformer comprising a fixed core generally rectangular in cross section and U-shaped, a

3 t l U-shaped movable core generally rectangular in cross sercin said holes in said movable core, said movable core tion, said U-shaped core having spaced legs and an interbeing movable toward and away `from said xed core,

mediate part connecting said legs together, the legs of thereby adjusting the length of flux path therein. said U-'shaped ixed core extending toward said movable core, a first `coil onV said movable core :and a second oil 5 References Cited by the Examiner on said iixed core, and elongated `cylindrical members UNITED STATES PATENTS xed to the ends of the legs of -said xed core received in 2,463,170 3/49 Grignon et al' 336-120 holes in said movable core and extending through the legs thereof, said cylindrical members being slidably received JOHN F BURNS, Primary Exllmnh 

1. A TRANSFORMER COMPRISING A U-SHAPED FIXED CORE HAVING LEGS AND AN INTERMEDIATE PART CONNECTING SAID LEGS TOGETHER AND A MOVABLE CORE DISPOSED WITH THE LEGS OF SAID U-SHAPED CORE FACING TOWARD SAID MOVABLE CORE, A FIRST COIL ON SAID FIXED CORE AND A SECOND COIL ON SAID MOVABLE CORE, CYLINDRICAL GUIDE CORE MEMBERS FIXED AT ONE END TO THE LEGS OF SAID U-SHAPED FIXED CORE AND EXTENDING THEREFROM GENERALLY PARALLEL THERETO, SAID GUIDE MEMBERS ON SAID FIXED CORE EXTENDING THROUGH THE LEGS OF SAID MOVABLE CORE AND SLIDABLY RECEIVING SAID MOVABLE CORE, AND MEANS TO ADJUST THE POSITION OF SAID MOVABLE CORE ON SAID GUIDE CORE MEMBERS WHEREBY THE LENGTH OF MAGNETIC CIRCUIT THROUGH SAID CORES IS INCREASED. 